Given the transmit signal \( \mathbf {s} \) , the problem of interest for OTFS radar sensing is to detect the presence of multiple targets and estimate their parameters, i.e., their gain-delay-Doppler triplets \(\lbrace (\alpha _k, \tau _k, \nu _k)\rbrace _{k=0}^{K-1}\) . This detection and estimation is done from the time domain observations in (REF ), or, equivalently, from its sampled version in (REF ). Unlike the existing works in the OTFS radar literature, e.g., [1]}, [2]}, [3]}, where estimator design is based on the received symbols in the delay-Doppler domain, we adopt a low-complexity approach that performs detection/estimation directly using time-domain observations without transforming them into delay-Doppler domain.
